This proposal deals with the study and perpetuation of a mutant strain of rats characterized by inherited hydronephrosis with ischemia, renal arteriosclerosis and arterial hypertension, thus making available a unique experimental model for the study of renal and cardiovascular pathophysiology. The renal lesion is inherited as an autosomal dominant trait and is lethal in homozygous conditions. This application requests funds to maintain the colony of animals carrying the mutation and to employ this experimental model in the following programs: 1) Determination of the blood pressure in intact, nephrectomized and adrenalectomized rats, to ascertain the role of the damaged and ischemic kidneys and adrenal glands in the pathogenesis of the hypertension. 2) Relationship between the age and severity of the renal disease to the development and degree of the hypertension. 3) Study of vasopressor substances released by the damaged kidneys as a mechanism of the hypertension, with particular attention to the renin-angiotensin system. 4) Effect of heterologous antirenin globulin on the arterial hypertension and levels of plasma renin. 5) Treatment of the hypertensive animals with therapeutic agents such as chlorothiazide, alpha-methyl dopa and reserpine, and 6) Histopathologic studies of the kidneys, adrenal glands and small and large arteries.